The Study of the Urinary D-lactate Concentration and Lactate Transporters Expression in Mice Renal Injury

• Main Authors: Tzu-Chuan Huang, 黃子娟
• Other Authors: 李仁愛
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/00265614814489306725

碩士 === 臺北醫學大學 === 藥學研究所 === 95 === D-lactate is associated with some human diseases such as diabetes mellitus and encephalopathy, and urinary D-lactate may be used as an indicator to determine the level of kidney damage in diabetic rats. Clinical and in vitro findings have previously suggested that the proximal tubule was the target of aristolochic acid (AA). In this study, the mice model of AA-induced nephropathy was used to investigate the relation between urinary D-lactate and renal injury. The proximal tubular lesions were induced by intravenous injections of AA at a high dose of 10 mg/kg body weight/day for 5 days and were characterized biochemically. Urinary excretion of proteins, urinary N-acetyl-beta-D-glucosaminidase (NAG), and plasma creatinine was determined. Urinary D-lactate was separated by our proposed column-switching high-performance liquid chromatography (HPLC) method with fluorescence detection. The expressions of lactate transporters, slc5a8 and MCT 2, in the proximal tubule of normal and AA treated mice kidney were studied by western blot analysis. The results showed that a remarkable increase of urinary markers including urinary proteins and urinary NAG, and the histological examination (PAS stain) confirmed the proximal tubule injury. The ratio of D-lactate (μM) to creatinine (mM) in the urine of AA treated mice were approximately 40-fold greater than that in control groups, which were 311.31 ± 71.7 and 8.60 ± 1.80, respectively. By Western blot analysis of lactate transporters, which have an affinity for D-lactate, we found that the expression of transporter MCT 2 and slc5a8 were decreased in AA treated mice. These data confirmed in vivo that urinary D-lactate reflected the renal injury conditions in AA-treated mice and may be a marker for the assessment of nephropathy.